The disclosure relates to a microfluidic storage device for pre-storing of fluid, to a method for its production and to a use thereof.
Lab-on-a-chip (LOC) systems are used in order to allow laboratory processes, which have previously been carried out by hand, to take place in an automated fashion in an integrated system. To this end, an LOC system comprises channels and cavities which, for example, are formed as mixing cavities or offer the possibility of allowing biochemical reactions to take place in the predetermined miniaturized volume region. The fluids or liquids necessary for this are either supplied from the outside via fluidic interfaces or pre-stored in the LOC system. Pre-storage makes it possible, inter alia, for the entire microfluidic system to remain closed and for a contamination risk to be reduced.
LOC systems often consist of a polymer layer system which is joined together during the construction or production process. For example, laser welding is used as the joining technology. During laser welding, a laser beam passes through a transparent assembly partner onto a light-absorbing assembly partner, the materials at the interface of the assembly partners being liquefied and mixing of the materials and a material-fit connection taking place. During the joining process, a force, or a compression pressure, may be exerted on the layer structure in order to ensure good contact between the assembly partners. To this end, the layer structure to be assembled is conventionally clamped between a base plate and a transparent pressure plate, for example a glass plate, so that the laser radiation can pass through the pressure plate, for example the glass plate, onto a surface region of the light-absorbing assembly partner.
The previously used possibilities for pre-storage of fluids or liquids in polymer layer systems, for instance LOC systems, include blister packages, integrated in the system, for pre-storing the fluids or reagents. A first example relating to this is an LOC system which is described in the article “Automated Closed-Vessel System for in Vitro Diagnostics Based on Polymerase Chain Reaction” by J. B. Findlay et al., Clinical Chemistry, Vol. 39 (9), pages 1927-1933 (1993). This LOC system comprises a multiplicity of storage vessels consisting of bubble-shaped blister containers. These containers are unclosed, however, which greatly restricts the possibilities for practical use. A second example relating to this is mentioned in the article “Clinical applications of a programmable nano-bio-chip” by J. V. Jokerst et al., Clinical Laboratory International, Vol. 33 (6), pages 24-27 (November 2009), relating to an exemplary commercially available nano-bio-chip from the company LabNow. In this case, burst valves are integrated in the system (microfluidic chip) in order to release the reagents from the blister packages, although it is difficult in terms of manufacturing technology to produce these valves with high process reliability.
The known possibilities for pre-storing fluids or liquids in polymer layer systems furthermore include dispensing fluids into previously formed cavities in a polymer layer and subsequently joining together the layer structure, for example by means of laser beam transmission welding, as described for instance in the dissertation (Ph.D. thesis) “Multilayer Pressure Driven Microfluidic Platform—μFLATLab” by J. Rupp, which was submitted to the technical faculty of Albert-Ludwigs University in Freiburg im Breisgau on 24, May 2011 (see http://www.freidok.uni-freiburg.de/volltexte/8374/pdf/111129_Rp_Dissertation_actual.pdf).